1. Field of the Invention
The invention relates to boring bars and refers more specifically to boring bars wherein radial adjustment of a cutting tool is accomplished on rotation of a boring bar body to which the cutting tool is secured in an eccentric bore in an adapter which is rotated about a center line parallel to but offset from the center line of the bore.
2. Description of the Prior Art
In prior boring bars wherein radial adjustment of a cutting tool has been accomplished by rotation of a boring bar body within an eccentric bore in an adapter, radial adjustment of the tool has required precise angular positioning of the boring bar body with respect to the adapter. Sometimes in the past, pre-stressed bearings have been provided between the boring bar body and the adapter in the bore to improve the ease of angular adjustment between the boring bar body and adapter. However, such adjustment must still be very precisely made and is subject to being disturbed during machining if the boring bar and adapter are not locked in adjusted position. If the boring bar body and adapter are locked in each adjusted position, the adjustment may be lost during the locking procedure. Also, the locking procedure takes time additional to the already undesirable time required for making the checking fine radial adjustment of the cutting tool.